Shingles and Neuropathic Pain

Shingles is caused by reactivation of the varicella zoster virus, which remains dormant in the dorsal root ganglia or sensory ganglia of the cranial nerve after a primary varicella infection, and when the virus reactivates, it travels along nerve pathways, causing inflammation and damage to nerves, resulting in the characteristic painful rash with dermatomal distribution 1, 2
The reactivation of the varicella zoster virus causes inflammation and damage to nerves, resulting in the characteristic painful rash with dermatomal distribution, and this nerve damage can lead to persistent neuropathic pain 1

Clinical Manifestations and Impact

Patients with postherpetic neuralgia may describe the pain as a "cold burning pain" typically in a glove-and-stocking distribution, and this condition can be incapacitating in patients with advanced disease and other immunocompromised states 3

First-line pharmacological treatments for postherpetic neuralgia include tricyclic antidepressants, such as amitriptyline, nortriptyline, and doxepin, as recommended by medical guidelines 4

The most effective strategy to prevent shingles, postherpetic neuralgia, and related complications is vaccination, with two types of herpes zoster vaccines available: zoster vaccine live and recombinant zoster vaccine, particularly important for older adults and those with compromised immune systems 1, 2
Vaccination with zoster vaccine live or recombinant zoster vaccine is recommended to prevent shingles and postherpetic neuralgia, especially in older adults and immunocompromised individuals 1, 2

Immunomodulator therapy should not be commenced during active infection with chickenpox or herpes zoster, and in the event of varicella zoster virus infection during immunomodulator therapy, antiviral treatment should be started promptly and immunomodulator therapy discontinued in severe cases if possible 5
People with weakened immune systems, such as those with HIV, have an increased risk of developing herpes zoster compared to the general population, and shingles is more severe in these patients, with an increased risk of postherpetic neuralgia 5

The American Academy of Dermatology recommends reserving corticosteroids for specific situations, such as acute, widespread flares requiring rapid symptom control, bridge therapy while initiating other treatments, and using prednisone 0.5-1 mg/kg daily for short courses (10-14 days maximum) 6

Older adults with shingles often have contraindications to systemic corticosteroids, including poorly controlled diabetes, labile hypertension, glaucoma, and history of peptic ulcer disease, according to the American Academy of Otolaryngology-Head and Neck Surgery 7

The American Academy of Microbiology, Immunology and Infection recommends vaccination as the most effective strategy to prevent shingles and PHN, with the recombinant zoster vaccine (Shingrix) being strongly preferred for adults ≥50 years, having 97.2% efficacy against shingles, 91.3% efficacy in those ≥70 years, and 88.8% efficacy against PHN 8, 9
The recombinant zoster vaccine (Shingrix) has a protection rate maintained >83% for up to 8 years, according to the Journal of Microbiology, Immunology and Infection 9
Zoster vaccine live (Zostavax) is an alternative but less effective, with 51.3% efficacy against shingles and 66.5% against PHN in those ≥60 years, and its efficacy wanes significantly over time, as reported by the Journal of Microbiology, Immunology and Infection 9